Secure Online/Offline Multi-Authority Attribute-Based Encryption for Resource-Constrained Devices in Cloud Computing

摘要

Multi-authority attribute-based encryption (MA-ABE) is regarded as a promising cryptographic technique to handle the problem of access control for data sharing, because it provides the fine-grained access control over encrypted data. However, most of the existing MA-ABE schemes suffer from the disadvantages of expensive computational cost and weak security. In this paper, we present a novel secure online/offline multi-authority attribute-based encryption scheme for resource-constrained devices in cloud computing. The proposed scheme reduces the online computation burden for data owners by completing the preprocessing computation as much as possible during the offline phase. The proposed scheme eliminates a major of computation overhead on the user side by migrating the partial decryption computation to the cloud servers. In order to guarantee data security, a Chameleon hash function is utilized to generate an immediate ciphertext embedded in the offline ciphertext. The proposed scheme is proven secure against adaptively chosen-ciphertext attacks. The extensive analytical comparisons and experimental results indicate that the proposed scheme is efficient and very suitable for resource-constrained devices.